As disclosed in Korean Patent Laid-open Publication No. 2011-0077860 (Jul. 7, 2011), a vacuum insulation material generally includes a core material for maintaining a shape of the insulation material while supporting a difference between an internal pressure and atmospheric pressure, an outer skin for interrupting gas to maintain the insulation material in a vacuum while sealing the core material, and a getter material for absorbing residual gas in the insulation material and other gases to maintain a vacuum for a long time.
Referring to FIG. 1, a vacuum insulation material 10 includes a core portion 11 including a core material 12 and an outer skin 14 enclosing the core portion 11, and a stick-type getter material 13 may be directly inserted into the core material 12.
The getter material 13 plays an important role in securing durability of the vacuum insulation material 10 for a long time, and such a conventional getter material 13 may absorb gas except for inert gas such as CO/CO2 and hydrocarbon gas in addition to N2, O2, and H2 that are main substances of air.
However, since the conventional getter material requires high raw material costs and heat treatment at a temperature of 300° C. or higher for activation before use thereof, and additionally include an adsorbent for absorption of moisture, thereby increasing manufacturing costs.